Intradermal nozzle for jet injection devices



y 14,1964 A. ISMACH 3,140,713-

INTRADERIAL uozzu: FOR JET nuscnou osvxcss Filed March 25, 1963 INVENTOR. A rzou \5MACH WQM United States Patent "ice 3,140,713 INTRADERMAL NOZZLE FOR JET INJECTION DEVICES Aaron lsmach, Brooklyn, N.Y., assignor to the United States of America as represented by the Secretary of the Army Filed Mar. 25, 1963, Ser. No. 267,869 1 Claim. (Cl. 128173) (Granted under Title 35, U.S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

With the development of the jet injection apparatus, and its adoption for mass inoculations and injections, it soon became apparent that extreme care had to be exercised in the control of the depth of an injection. Needless to say, some injections are intended to be intramuscular; some are intended to be subcutaneous with a minimum of muscular penetration; and others, such as the smallpox vaccine, are frequently intended to be administered intradermally.

It is an object of this invention to provide, in a conventional jet injection apparatus such as, but not limited to, that described in Patent No. 3,057,349, an intradermal nozzle which would permit control of the depth of the vaccine penetration in the dermis.

Another object of this invention is to provide, in an intradermal nozzle for a conventional jet injection device, a means of determining the maximum force that the nozzle orifice can exert against the injection site without regard to the force exerted by the operator of the jet injection device.

Variables which determine the characteristics of a given injection are: the angle of mounting of the orifice in the nozzle, the contour of the cap, and the force of the injection. If the angle between the surface of the skin and the orifice in the nozzle is too large, depth of penetration is diificult to control. If this angle is too small, on the other hand, slicing of the skin occurs. It has been found through experimentation that an orifice angle of approximately 45 degrees produces the most successful results. The contour of the nozzle shapes the skin to receive the stream from the orifice of the nozzle. I have found that optimum conditions exist when the outgoing surface of the nozzle (the outer forward surface) runs parallel to the exist stream and at a distance of approximately of an inch.

Though not directly concerned with in this invention, the initial injection force, the third critical element, should be sufficient to insure penetration for all individuals regardless of the type of skin, with care being taken to insure that excessive force, leading to excessive tearing of the skin, is not used. Generally speaking, a force of from fifty to sixty percent of that required for subcutaneous or intramuscular injections is suitable for intradermal type injections according to the instant invention.

Other objects of my invention will become apparent to 3,140,713 Patented July 14, 1964 those skilled in the art upon reference to the drawings in which:

FIG. 1 is a sectional view of a nozzle of a conventional hypodermic jet injection apparatus which has been modified in accordance with the instant invention for intradermal injection.

In brief, this invention comprises a nozzle with an orifice set at an angle of 45 degrees from a longitudinal axis of the hypodermic jet injection apparatus. Surrounding the orifice is a concentric forwardly protruding shoulder.

Referring in more detail to the drawing, sapphire orifice insert 1 is so disposed as to control a stream at an angle of approximately 45 degrees from the longitudinal axis of the gun and parallel to inner surface 2 of shoulder 3. As stated above, the most effective distance between injection stream 4 and surface 2 is inch for intradermal injections. Shoulders 3 may be an integral part of the nozzle or, where conversion of standard caps is desired, may be in the form of a cap to be placed over the standard nozzle. As can easily be seen, when thefront of this nozzle is placed against the skin, the shoulders of the nozzle shape or form the skin to receive the stream from the injection device. It can also be seen that with the stream running parallel to the inner face of the nozzle, the criticality of the depth of penetration along the axis of penetration is reduced substantially.

The angle type nozzle described thereby overcomes the basic difficulty usually encountered in giving intradermal injections by jet. Where the vaccine enters normal to the skin, the normal variations in the toughness of the skin of different individuals, under the same injection force setting, can result in a range varying from no penetration where the skin is tough to subcutaneous injection where the skin is tender (as in the case of women and children). The angle type nozzle is designed to have a vaccine enter the skin tangentially to the surface so that once there is sufiicient initial force to enter the skin, the intradermal target area is very large and penetration in depth, normal to the surface, cannot occur.

I claim:

In a hypodermic jet injection device an intradermal nozzle comprising an orifice with a longitudinal axis angularly offset with respect to the longitudinal axis of the device, said offset being at an angle of approximately 45 degrees, and a shoulder encircling and extending distally of said orifice with the inner surface of said shoulder at one point substantially parallel to the axis of said orifice and at a distance of approximately of an inch from said orifice.

References Cited in the file of this patent UNITED STATES PATENTS 2,322,244 Lockhart June 22, 1943 2,704,542 Scherer Mar. 22, 1955 FOREIGN PATENTS 677,523 Great Britain Aug. 20, 1952 

